Development of a new correlation for single-sided natural ventilation adapted to leeward conditions

When a wind flow approaches a building, a recirculation zone is created on the leeward side of the building. This turbulent zone behind the building increases the air mixing at the leeward openings between entering and leaving air. As a consequence the effective temperature difference is reduced at the opening, counteracting the stack effect. Therefore, the air change rate is lower than that in absence of wind.Some empirical correlations have been set up to assess the airflow rate due to the combination of stack and wind effects. However these correlations do not take into account the reduction of airflow rate in leeward conditions.This paper aims to improve the existing correlations and in particular to confront the issue related to leeward openings. The study is based on CFD simulations and full scale experiments. A comparison of Warren's correlation with CFD and experimental results shows that this correlation captures well the stack and wind effects in windward conditions but shows poor results in leeward conditions. Thus, a new correlation has been developed by using CFD simulations in leeward conditions. The new correlation is then compared with the full-scale experiments and concords well.

► We propose a new correlation of air change rate for single-sided natural ventilation in leeward conditions.
► We use CFD to analyze the physical phenomena and to develop the new correlation of air change rate.
► The wind plays the role of air mixing at the window opening, counteracting the stack effect.
► The wind effect in leeward conditions is badly captured by the existing correlations.
► The new correlation is validated by comparison with in situ experimental data.